Reports of the withdrawal were first reported by Spain's Marca earlier in the week.

Djokovic's withdrawal means No. 2 Roger Federer will be the top seed and No. 5 Kei Nishikori, who won Barcelona and made the Madrid final last year, will get bumped up to the No. 4 seed.

Based on his success through the first four months of the season and his desire to keep his body rested for his upcoming charge at the French Open, Djokovic has opted to skip Madrid for the second year in a row. Last year he withdrew due to an arm injury. Djokovic made history two weeks ago when he became the first man in the Open Era to win the first three Masters tournaments of the season, having captured the titles at Indian Wells, Miami and Monte Carlo.

​With his Monte Carlo win, Djokovic tied Federer with 23 Masters titles, second only to Rafael Nadal. But the French Open has been the elusive trophy missing from Djokovic's resume. A win at Roland Garros will complete his career Grand Slam and establish him as one of the best all-court players the game has seen. He has lost to Nadal in each of the last three years in Paris, twice in finals. That he has chosen to take some additional rest by skipping Madrid, a tournament with altitude conditions that do not mirror those in Paris, is no surprise.

While the Madrid Open is a mandatory ATP event, Djokovic has earned an exemption under the rules given his length of service and is allowed to skip one mandatory event without any penalties. The ATP rules allow a player to skip one mandatory event if he has (1) played more than 600 matches in his career, (2) been on tour for 12 years, or (3) reaches the age of 31. If a player reaches all three milestones, as Federer has, he may skip any and all Masters without penalty.

Djokovic's next tournament will be the Italian Open in Rome, Italy, which begins on May 10th.